The number of fibers from known classes of high performance polymers which are useful under severe environmental conditions is limited. In addition, some of the known classes of polymers are deficient in some properties, e.g., physical properties, solvent and thermal resistance, and processability. Some are also quite expensive.
Developments in the synthesis of rigid rod-like polymers have generated interest in forming composites by blending those polymers with conventional flexible coil polymers. This interest is based on potential improvements in fracture and impact toughness as well as other properties. In other words, the rigid rod-like polymer might behave as a strength member in a ductile matrix while the flexible matrix might provide toughness. However, achieving the potential benefits has been elusive in practice.